I feel that the new 1.4 patch simply has some issues like that. What you can do is reinstall your game, and before that try to move your Crusader.cfg file elsewhere. I mean, I think it might be good to remove it from the Documents\Stronghold Crusader folder, but make sure that you back it up.

Then when you reinstall the game everything should work well again. But, this way you would lose all your games progress - your Crusader Trail progress, campaign progress, etc.

But after you reinstall the game you may try to make a copy of your new Crusader.cfg file, and try to put your old .cfg file into the folder. Just to make sure if the problem is caused by incompatible .cfg file, or it is simply in the game... The best would be if you could make it work with your old .cfg file, but if not, you can download somebody else' .cfg file - if you don't feel like winning the campaigns and the trails all over again.

Let us know what you managed to do.

Oh, and I just assumed that you have the Steam version of the game? If it is not Steam, then perhaps it might be the best to use an older version instead, such as 1.1, or 1.2, or 1.3. BUT, if it is the Steam version, then you should try backing up the .cfg file, and verifying the games files integrity. That you can do by right-clicking the game in your Steam library, picking Properties, going to the Local Files tab, and hitting the Verify Integrity of Game Files. If that doesn't do the trick, try what I described above.